The present invention relates to an inductance device used in various electronic apparatuses.
A conventional inductance device is described hereinafter with reference to the accompanying drawings. Japanese Patent Application Non-Examined Application No. H10-294221 discloses one of the conventional inductance devices. FIG. 10 is a perspective bottom view of the conventional inductance device, and FIG. 11 is an exploded perspective view of the inductance device shown in FIG. 10.
In FIG. 10 and FIG. 11, the conventional inductance device comprises the following elements:
drum core 24;
winding 25;
ring core 26; and
terminals 27.
Drum core 24 has upper brim 22 on a first end of roller shaft 21 and lower brim 23 on a second end of roller shaft 21. Diameters of those two brims are approx. the same. Winding 25 is wound on shaft 21. Ring core 26 has a sectional view of a ring shaped hollow-cylinder, and is disposed outside drum core 24. Ring core 26 is fixed to drum core 24 with adhesive. Respective two terminals 27 are mounted to ring core 26, and electrically connected to the two winding-ends.
One of each terminal 27 has mount-section 28 to be mounted to a board of an apparatus, and fit-section 29 to be fitted to ring core 26. Each terminal 27 is fitted to ring core 26 from the outside such that the two terminals are on diagonally opposite positions.
When this conventional inductance device is mounted on a board, drum core 24 is positioned such that a space is provided between lower brim 23 and the board.
In this conventional structure, drum core 24 and ring core 26 are supported by only two fit-sections 29, and mounted to the board. In general, cores 24 and 26 are fragile because they are made of sintered magnetic material such as ferrite. Therefore, when a shock is applied to this conventional inductance device, cracks occur on ring core 26 around fit-section 29. Both of drum core 24 and ring core 26 thus sometimes fall away from the board leaving vicinity of fit-sections 29 of terminals 27 on the board. As such, the conventional inductance devices are vulnerable to shocks.
The present invention addresses to the problem discussed above, and aims to provide an inductance device of which shock-proofness is improved. The inductance device of the present invention is thus free from falling away from a mounted-board with fit-sections of terminals left on the board when a shock is applied to the drum core or the ring core.
The inductance device of the present invention comprises the following elements:
(a) a drum core having an upper brim on a first end of a roller shaft and a lower brim on a second end of the roller shaft;
(b) a winding wound on the roller shaft;
(c) a ring core having grooves, disposed outside the drum core and fixed to the drum core; and
(d) terminals, for connecting electrically the winding thereto, including:
(d-1) fit-sections for fitting the terminals to the ring core by putting parts of the respective fit-sections into the grooves; and
(d-2) mount-sections, for mounting the inductance device to an apparatus, linked to the respective fit-sections and extending inward along the lower brim of the drum core from near perimeter of the ring core.
When a shock is applied to the inductance device of the present invention, the structure discussed above allows the shock applied to the drum core or the ring core to disperse into the mount-sections of the terminals. The stresses applied to the fit-sections of the terminals are thus relaxed. As a result, cracks on the ring core around the fit-sections can be restrained, and the shock-proofness of the inductance device is improved.